LaCo1 - xFexO3 (x ranging from 0 to 1) nanoparticles were prepared using the co -precipitation method, and the CO gas sensing properties of LaCo1 - xFexO3 nanoparticles were investigated. The LaCo0.3Fe0.7O3 sensor shows the highest response at 250 degrees C (S = 40.9), and reliable dynamic response-and-recovery to different CO concentrations at a temperature as low as 50 degrees C. On the other hand, the LaC0.2Fe0.8O3 sensor exhibits the fastest response and recovery in the entire temperature region of 250 to 450 degrees C. The excellent CO sensing properties could be ascribed to the intense oxidation of CO by adsorbed O-2 on the LaCo1 - xFexO3 (x = 0.6, 0.7, 0.8) surface. (C) 2017 Elsevier B.V. All rights reserved.